Cornus alba Elegantissima named `Staltouch`

ABSTRACT

This invention comprises a new and distinct variegated dogwood. It is a selected sport that occurred naturally from a group planting of Cornus alba `Argenteo-marginata` (C.a. `Elegantissima`) at my nursery five years ago. I have successfully propagated this sport asexually by cuttings. The small compact growth habit is what characterizes and makes this new selection distinctive.

BACKGROUND OF THE INVENTION

Cornus alba is a red stemmed shrub used widely for landscaping purposes.It is an introduction from Europe/Asia, thought to have occurred in1741. (Rehder) A particularly popular variety has variegated leaves. Thewhite margins of the leaves make it distinctive. Variations do occur inthe size of the leaves and in the width of the white (or ivory) margin.This may account for the differences in nomenclature. It is known by anassortment of botanical names, as follows:

Cornus alba `Elegantissima`: Hillier Dictionary of Plants.

Cornus alba `Argenteo-marginata`: Rehder & Dirr & Hortus III.

Cornus alba elegantissima variegata: Rehder & Hortus III.

Cornus alba variegata: Rehder.

Cornus alba `Sibirica Variegata`: Hortus III.

The current usage seems to favor Cornus alba `Argenteo-marginata`. Outof a block of Cornus alba `Argenteo-marginata` (C.A. `Elegantissima`), Idiscovered a plant that was growing a fraction of the height of thebalance of the Cornus alba `Argenteo-marginata` plants. I propagatedthis unique plant to see if it would retain the dwarf characteristics aswell as the variegated foliage of the parent plant.

The first sport was propagated as softwood cuttings in Madison, Ohio, inJune of 1992, with 90% rooting. These original cuttings become theplants which would serve as the parent stock for early cutting material.Subsequent softwood cuttings have exhibited high rooting success(90-98%) using common practices, under a misting type system. Hardwoodcuttings have been used as propagation material with equal success.Ocassionally, a propagated plant will convert to the more aggressivegrowth of the parent plant. This has occurred less than 1% of the time.These reverted plants are easy to distinguish and cull out because ofthe greater stem length (internodal dimensions, see Table 1 thatfollows). Rooting has been successful without any application of rootinghormones. It is believed that any standard practice that is successfulwith any Cornus alba would be successful with this new selection. Plantsof this new selection that have rooted and are grown on for five yearscontinue to exhibit the dwarfing characteristics of the original motherplant.

Having grown this new cultivar along side Cornus alba`Argenteo-marginata` for five years, it exhibits the same hardiness,which is Zones 3-7 according to the USDA Plant Hardiness Zone Map. Allother horticultural characteristics with the exception of thosedescribed below are the same as Cornus alba `Argenteo-marginata`.

The uniqueness of this new cultivar is that of a small compact growthhabit as compared to its parent plant, Cornus alba `Argenteo-marginata`.It retains the ornamental characteristics of the parent plant, namelythe white-edged, variegated foliage that makes Cornus alba`Argenteo-marginata` popular. The characteristics of `Staltouch` make itparticularly suitable for planting against darker plantings, e.g.,Taxus, in rock gardens, as surround plants around specimen trees, etc.The plant's distinguishing characteristics are described in detailbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photograph that shows the variegated foliage as comparableto the standard Cornus alba `Argenteo-marginata`. Also, FIG. 1 exhibitsthe burgundy blush that occurs on the new growth as the plants areleafing out. This burgundy blush becomes more prevalent as part of thefall color.

FIG. 2(A)-(C) is a photograph comparing (A.) this new cultivar with (B.)a popular cultivar called `Ivory Halo`™ (U.S. Plant Pat. No. 8,722) andwith (C.) the standard Cornus alba `Argenteo-marginata`. This photographindicates that shorter internodal length of `Staltouch` compared to thestandard Cornus alba `Argenteo-marginata`.

DETAILED BOTANICAL DESCRIPTION

The following observations were made on a three year old rooted cuttingof the mother plant of `Staltouch`. Morphological characteristics aredescried with respect to a standard `Cornus alba `Argenteo-marginata`and Cornus alba `Bailhalo` (`Ivory Halo`™; U.S. Plant Pat. No. 8,722).Color designations are made in accordance with The Royal HorticulturalSociety Colour Chart (R.H.S.).

Origin: sport from Cornus alba `Argenteo-marginata`.

Plant:

Growth habit.--dwarfed and spreading in comparison to Cornus alba`Argenteo-marginata` and Cornus alba `Bailhalo`.

Spread/height/ratio--.38.1 cm (15 in)/55.9 cm (22 in)=1.47. This is 199%more spreading than Cornus alba `Argenteo-marginata` (see Table 1).

Branches.--multibranched in the absence of pruning; primary branchesarising from crown.

Stolons.--None.

Rhizomes.--None.

Leaves:

Shape.--lanceolate and variegated with irregular white margins.

Size.--Length: 75.3 mm mean; standard deviation (s.d.) +/-4.9 mm;Coefficient of Variability (C.V.) 6.5%; Confidence-Limits (C.L.)90%=72.0-78.5 mm. This length is 75.3% of the length of the Cornus alba`Argenteo-marginata` leaves (see Table 2).

Width: 35.5 mm mean; s.d. +/-3.6 mm; C.V. 11.2%; C.L. 90% =33.1-37.9 mm.This width is 82.1% of the length of the Cornus alba`Argenteo-marginata` leaves (see Table 2).

Color.--Summer: Grey green (R.H.S. 139C) with irregular white or nearwhite (R.H.S. 157A) variegated edges.

New growth and fall color: Burgundy (R.H.S. 59A) with irregular white tored-purple (R.H.S. 65A) variegated edges.

Stems:

Shape.--Erect.

Size.--A 300 mm long branch had 14 internodes, no pruning cuts, and 11naturally occurring secondary branches. Stems are 50% smaller indiameter and more numerous than on Cornus alba `Argenteo-marginata`.

Internodes.--mean=21.4 mm; s.d +/-8.8 mm; C.V. 40.8%; C.L. 90%=17.3-25.6mm. The mean internode length is only 60.8% of that of Cornus alba`Argenteo-marginata`.

Color.--Blood-red in winter, usually greener in summer with leaves. Pithis white.

Flowers:

Appearance.--sparsely, in cymes, 3.5 to 5 cm across.

Color.--yellowish white, typical for Cornus alba.

                  TABLE 1    ______________________________________    Height and Spread:                             INTERNODE  HEIGHT/             HEIGHT PRUNED   MEAN       SPREAD    ______________________________________    Cornus alba               26 in.   3× 35.5     0.74    `Argenteo-    marginata`    Cornus alba               18 in.   1× 28.9     1.06    `Baihalo`    Cornus alba               15 in.   0× 21.4     1.47    `Staltouch`    ______________________________________

                  TABLE 2    ______________________________________    Leaf and Stem Dimensions:    ______________________________________           MILLIMETERS    ______________________________________    C. alba    `Elegantissima`    Leaf Length             127    119    101  92   99   104  75   83    Leaf Width             55     51     41   41   44   40   33   41    Internodes             21     40     61   57   49   32   25   43    C. alba    `Bailhalo`    Leaf Length             84     108    98   94   107  117  90   81    Leaf Width             39     49     51   52   47   59   47   34    Internodes             47     54     50   38   18   11   12   24    C. alba    `Staltouch`    Leaf Length             75     70     84   77   69   72   74   81    Leaf Width             35     33     34   36   30   34   39   43    Internodes             36     38     29   18   18   23   23   23    ______________________________________                                 s.d.        C.           MILLIMETERS   MEAN    +/-    C.V. I.    ______________________________________    C. alba    `Elegantissima`    Leaf Length                          100   17.3 17.3 90    Leaf Width                           43.3  6.9  15.9 90    Internodes             36    33    8               35.3  15.9 45.0 90    C. alba    `Bailhalo`    Leaf Length                          97.4  12.6 12.9 90    Leaf Width                           47.3  7.8  16.4 90    Internodes             32    31    25  22  12      28.9  14.7 50.9 90    C. alba    `Staltouch`    Leaf Length                          75.3  4.8  6.5  90    Leaf Width                           35.5  3.6  11.2 90    Internodes             23    19    15  18  12  5   21.4  8.8  40.8 90    ______________________________________     mean  in mm     s.d. = standard deviation, in mm     C.V. = coefficient of variability, in %     C.L. = confidence limits, in %

REFERENCES

Manual of Cultivated Plants, Alfred Rehder, Macmillan Co.

The Royal Horticultural Society Colour Chart, Royal HorticulturalSociety of England

USDA Plant Hardiness Zone Map

Hillier's Manual of Trees and Shrubs, Yelf Brothers Limited

Hortus III, L.H. Bailey Hortorium, Cornell University

Photographic Manual of Woody Landscape Plants, Michael Dirr, StipresPublishing Co.

I claim:
 1. A new and distinct cultivar of dogwood (Cornus alba`Argenteo-marginata`) plant designated `Staltouch`, as herein shown asdescribed, characterized by its unique compact growth habit, spreadingappearance, and fine dense branching.